Periodontal Disease and Overall Health: A Clinician's Guide

CHAPTER 2Overview of Periodontal Disease:Causes, Pathogenesis, andCharacteristicsYing Gu, Maria E. RyanINTRODUCTIONPeriodontal diseases are serious chronicinfections that involve destruction of thetooth-supporting apparatus, including thegingiva, the periodontal ligament, and alveolarbone. These diseases are initiated by alocal accumulation of bacteria adjacent tothe tooth. Periodontal diseases, includinggingivitis and periodontitis, can affect onetooth or many teeth and, if left untreated,can lead to tooth loss, particularly in adults.It is the most common dental condition inadults, and is also one of the most commonchronic inflammatory diseases affecting amajority of the population throughout theworld. Although plaque is essential for theinitiation of periodontal diseases, the majorityof the destructive processes associatedwith these diseases are due to an excessivehost response to the bacterial challenge.Therefore, periodontal disease is a multifactorial,complex disease. The purpose of thischapter is to provide a general overview ofthe types of periodontal disease, risk factorsassociated with them, and the etiology,pathogenesis, and management of periodontaldiseases.TYPES OF PERIODONTAL DISEASEPeriodontal diseases include two generalcategories based on whether there is attachmentor bone loss: gingivitis and periodontitis.Gingivitis is considered a reversibleform of the disease, and generally involvesinflammation of the gingival tissues withoutloss of connective tissue attachment. 1Periodontitis has been defined as the presenceof gingival inflammation at sites wherethere has been a pathological detachment ofcollagen fibers from cementum, the junctionalepithelium has migrated apically, andbone loss can be detected radiographically.The inflammatory events associated withconnective tissue attachment loss lead tothe resorption of coronal portions of toothsupporting alveolar bone. 2 The understandingof periodontal disease is continuouslychanging as new research evidence emerges.There fore, the classification of periodontaldisease has changed since the system developedat the 1989 World Workshop in ClinicalPeriodontics. The classification presentedin this chapter is based on the results developedat the 1999 International Workshop organizedby the American Academy of Perio -dontology (AAP).The classification of periodontal diseasesnow includes eight general types 3 :1. Gingivitis2. Chronic periodontitis3. Aggressive periodontitis4. Periodontitis as a manifestation ofsystemic diseases5. Necrotizing periodontal diseases6. Abscesses of the periodontium7. Periodontitis associated with endo -dontic lesions8. Developmental or acquired deformitiesand conditionsThe overall classification system ispresented in Table 1. 3 In addition, the aboveclassification is different from case types